Engine starts and immediately dies

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mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
97 Disco

I've read a number of posts on this issue, but not sure any of them mirror my scenario exactly.

This started happening suddenly. From a cold start and fully charged battery the truck will fire up and immediately cut off (no rough idle, immediately). Repeated attempts to start the truck will NOT start at all, just hear the starter struggling. I don't know exactly how long it takes to "reset" where I get the initial startup, but it does the same thing if I try after 24 hours (starts up, dies, then won't start at all).

I've seen mention of electrical issues, fuel filter (which I'm sure does need replaced), fuel rails, fuel pump, etc.

I recently replaced the alternator and it seemed to run fine after that...this started happening a few weeks later. Only other recent change is I ran a power cable to an audio amp (which I now have disconnected). Maybe I jostled a connection when monkey around in the engine bay?

Any thoughts as to what would be the most likely culprit? I'm a novice mechanic, but persistent ;)

Appreciate any help y'all can offer...
 
M

mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
yes, as mentioned, fully charged battery. the first time I try it the starter turns the engine and it fires right up, then dies immediately. subsequent tries, I hear the starter, but engine won't start.
 
Spark6

Spark6

Well-known member
Oct 31, 2020
127
40
New Hampshire
Does it die at about 550 RPM? If so, you may have an MAF sensor issue. If the ECM doesn't receive an MAF signal by 550, it'll shut the motor down. (I recently learned this as part of my ongoing bug-hunt to fix a no-start issue.) Do you have the RAVE manual? That has been huge for us.
 
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robertf

Well-known member
Jan 22, 2006
4,789
360
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Spark6 said:
Does it die at about 550 RPM? If so, you may have an MAF sensor issue. If the ECM doesn't receive an MAF signal by 550, it'll shut the motor down. (I recently learned this as part of my ongoing bug-hunt to fix a no-start issue.) Do you have the RAVE manual? That has been huge for us.
Click to expand...

I forget to plug the MAF in everytime I change airfilters and its never done this
 
Spark6

Spark6

Well-known member
Oct 31, 2020
127
40
New Hampshire
mc9735 said:
I just went to test it again and yes, it dies right about 500 RPMs. I do have the RAVE.
Click to expand...

My input is likely a bit of the blind leading the blind, but I've found the workshop manual to include some helpful troubleshooting tips. Sounds like you need section 19, if you're not in there already. There is a pretty concise description of the MAF, its operation and its fault modes.
 
M

mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
I tried unplugging the MAF sensor, that didn't help...still no start. Is it worth trying to clean the MAF sensor? Soak it in alcohol in a bag and shake it around a bit? MAF cleaner? Is it worth trying to test it with a DMM? I'm not getting any check engine codes, fyi...should have mentioned that.
 
M

mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
...and one more thing to add in case it helps with diagnostic: prior to this "no start" situation, sometimes (esp after wet weather) the truck would start fine but then it would sputter under acceleration and couldn't get past 2k RPMs...this would sometimes go on for 30 minutes (basically i'd have to drive around a parking lot as it couldn't do more than 20 mph)...after that time it would drive as normal. Some on this forum suggested TPS or CPS could be culprit, but I never replaced them as I *thought* I was past this issue (hadn't happened in a while).
 
M

mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
is that the same as ECM (Engine Control Module) located by washer fluid reservoir? I've never messed with that...it's behind a cover with snaps? Easy to remove?
 
Spark6

Spark6

Well-known member
Oct 31, 2020
127
40
New Hampshire
mc9735 said:
is that the same as ECM (Engine Control Module) located by washer fluid reservoir? I've never messed with that...it's behind a cover with snaps? Easy to remove?
Click to expand...
Yes it is. And no, it’s not bad to get at. You’ll need to pull the washer fluid reservoir. Be gentle with the hose connections... :rolleyes:
 
M

mc9735

Active member
Apr 29, 2017
41
3
Chattanooga
Can I try spraying starter fluid into the air intake, or is that a no-no? If it starts up that way wouldn't it at least suggest it could be a fuel supply issue?

I don't have a fuel pressure gauge, but with ignition in ON position I poked the needle on the schrader valve and no fuel came out :( If it's a bad fuel pump (how common is that?) would that possibly explain the erratic idle and other weird issue I listed above (inability to accelerate for up to 30 mins)?

Should also add, truck sat for over a year before I got it, and I'm pretty sure the fuel filter was never changed. Maybe it's not the pump but a clogged filter (I hope)? 134k miles.
 
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